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1.
BMC Genomics ; 25(1): 380, 2024 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-38632506

RESUMO

BACKGROUND: Trombiculid mites are globally distributed, highly diverse arachnids that largely lack molecular resources such as whole mitogenomes for the elucidation of taxonomic relationships. Trombiculid larvae (chiggers) parasitise vertebrates and can transmit bacteria (Orientia spp.) responsible for scrub typhus, a zoonotic febrile illness. Orientia tsutsugamushi causes most cases of scrub typhus and is endemic to the Asia-Pacific Region, where it is transmitted by Leptotrombidium spp. chiggers. However, in Dubai, Candidatus Orientia chuto was isolated from a case of scrub typhus and is also known to circulate among rodents in Saudi Arabia and Kenya, although its vectors remain poorly defined. In addition to Orientia, chiggers are often infected with other potential pathogens or arthropod-specific endosymbionts, but their significance for trombiculid biology and public health is unclear. RESULTS: Ten chigger species were collected from rodents in southwestern Saudi Arabia. Chiggers were pooled according to species and screened for Orientia DNA by PCR. Two species (Microtrombicula muhaylensis and Pentidionis agamae) produced positive results for the htrA gene, although Ca. Orientia chuto DNA was confirmed by Sanger sequencing only in P. agamae. Metagenomic sequencing of three pools of P. agamae provided evidence for two other bacterial associates: a spirochaete and a Wolbachia symbiont. Phylogenetic analysis of 16S rRNA and multi-locus sequence typing genes placed the spirochaete in a clade of micromammal-associated Borrelia spp. that are widely-distributed globally with no known vector. For the Wolbachia symbiont, a genome assembly was obtained that allowed phylogenetic localisation in a novel, divergent clade. Cytochrome c oxidase I (COI) barcodes for Saudi Arabian chiggers enabled comparisons with global chigger diversity, revealing several cases of discordance with classical taxonomy. Complete mitogenome assemblies were obtained for the three P. agamae pools and almost 50 SNPs were identified, despite a common geographic origin. CONCLUSIONS: P. agamae was identified as a potential vector of Ca. Orientia chuto on the Arabian Peninsula. The detection of an unusual Borrelia sp. and a divergent Wolbachia symbiont in P. agamae indicated links with chigger microbiomes in other parts of the world, while COI barcoding and mitogenomic analyses greatly extended our understanding of inter- and intraspecific relationships in trombiculid mites.


Assuntos
Borrelia , Microbiota , Orientia tsutsugamushi , Tifo por Ácaros , Trombiculidae , Wolbachia , Animais , Tifo por Ácaros/epidemiologia , Tifo por Ácaros/microbiologia , Trombiculidae/genética , Trombiculidae/microbiologia , Wolbachia/genética , Filogenia , Borrelia/genética , Tipagem de Sequências Multilocus , RNA Ribossômico 16S/genética , Arábia Saudita , Orientia tsutsugamushi/genética , Roedores/genética , DNA , Orientia
2.
Indian J Med Res ; 159(2): 180-192, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38494626

RESUMO

BACKGROUND OBJECTIVES: Scrub typhus, caused by Orientia tsutsugamushi present in small mammals harbouring the ectoparasites. A study was undertaken to detect the pathogen present in small mammals and its ectoparasites in the scrub typhus-reported areas. METHODS: The small mammals (rodents/shrews) and its ectoparasites were screened for O. tsutsugamushi using nested PCR amplification of the groEL gene. Small mammals were collected by trapping and screened for ectoparasites (mites, ticks and fleas) by combing method. RESULTS: All the chigger mites collected were tested negative for O. tsutsugamushi . Interestingly, adult non-trombiculid mites ( Oribatida sp., Dermanyssus gallinae ), fleas ( Xenopsylla astia, X. cheopis, Ctenophalides felis and Ctenophalides sp.) and ticks ( Rhipicephalus sanguineus , R. haemaphysaloides ) screened were found to be positive for O. tsutsugamushi , which the authors believe is the first report on these species globally. Bandicota bengalensis with O. tsutsugamushi infection is reported for the first time in India. The O. tsutsugamushi groEL sequences from the positive samples were similar to the reference strains, Karp and Ikeda and phylogenetically clustered in clade IV with less evolutionary divergence. The blood samples of Rattus rattus , Suncus murinus and B. bengalensis collected from this area were tested positive for O. tsutsugamushi ; interestingly, the sequence similarity was much pronounced with their ectoparasites indicating the transmission of the pathogen to host or vice versa . INTERPRETATION CONCLUSIONS: The outcome of the present investigations widened our scope on the pathogens present in ectoparasites and rodents/shrews from this area. This will help to formulate the required vector control methods to combat zoonotic diseases.


Assuntos
Orientia tsutsugamushi , Tifo por Ácaros , Carrapatos , Trombiculidae , Ratos , Animais , Tifo por Ácaros/epidemiologia , Orientia tsutsugamushi/genética , Musaranhos , Índia/epidemiologia , Roedores/parasitologia , Trombiculidae/genética
3.
Zootaxa ; 5406(2): 343-358, 2024 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-38480149

RESUMO

Two new chigger species, Leptotrombidium mondulkiri sp. nov. and Walchia keoseima sp. nov., and one new subspecies, Leptotrombidium pilosum cambodiensis subsp. nov., are described from Cambodia. Three species, Walchia lupella (Traub and Evans, 1957), W. micropelta (Traub and Evans, 1957), and W. kritochaeta (Traub and Evans, 1957), are for the first time reported from the country. A redescription of W. lupella is given based on new materials from Cambodia and Thailand.


Assuntos
Trombiculidae , Animais , Camboja
4.
Vet Parasitol Reg Stud Reports ; 49: 101004, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38462305

RESUMO

The genus Perissopalla Brennan and White (Trombidiformes: Trombiculidae) is currently represented by ten species with three from Brazil: Perissopalla barticonycteris Brennan, Perissopalla ipeani Brennan, and Perissopalla tanycera Brennan. In the present study, these three species are redescribed and illustrated based on the types and additional non-type specimens. New host and locality records for P. ipeani and P. tanycera are included. Additionally, a partial sequence for the 18S rRNA gene for P. ipeani was provided.


Assuntos
Trombiculidae , Animais , Trombiculidae/genética , Brasil/epidemiologia , RNA Ribossômico 18S/genética
5.
Exp Appl Acarol ; 92(2): 203-215, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38321310

RESUMO

The red palm mite Raoiella indica Hirst, 1924 (Acari: Tenuipalpidae) is an important pest of the coconut palm Cocos nucifera L. (Arecaceae) and has caused problems in coconut production worldwide. Research has been carried out aiming at controlling the mite through chemical, biological, alternative, and host plant resistance methods. Identifying coconut palm cultivars resistant to R. indica is important to reduce the problems caused to plantations. Therefore, the objective of this work was to evaluate the performance of R. indica in six dwarf coconut palm cultivars, to identify sources of resistance. The cultivars of the sub-varieties green, red, and yellow evaluated were Brazilian Green Dwarf-Jiqui (BGDJ), Brazilian Red Dwarf-Gramame (BRDG), Cameroon Red Dwarf (CRD), Malayan Red Dwarf (MRD), Brazilian Yellow Dwarf-Gramame (BYDG), and Malayan Yellow Dwarf (MYD). Confinement and free choice tests of R. indica on the cultivars were performed, in which biological parameters and preference were evaluated. Mite performance was different in the cultivars evaluated. In the confinement bioassay, R. indica had the worst performance in the cultivar BGDJ, the best performance in CRD, MRD, and BRDG, and intermediate performance in BYDG and MYD. In the free choice test, the cultivars MRD and MYD were preferred in relation to BGDJ, and CRD was less preferred in relation to BGDJ. Therefore, we considered that the cultivar BGDJ is the most resistant to R. indica, by antibiosis and antixenosis; CRD has resistance by antixenosis; and MRD, BRDG, BYDG, and MYD are susceptible.


Assuntos
Arecaceae , Ácaros , Trombiculidae , Animais , Cocos , Brasil
6.
Parasitol Res ; 123(1): 83, 2024 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-38182821

RESUMO

Nine species-level taxa of bat ectoparasites, three chigger mites (Trombiculidae), three hard (Ixodidae), and one soft tick (Argasidae) species, as well as two bug (Cimicidae) species from nine bat species hosts were detected in the Eastern Palaearctic. Trombiculid larvae of Leptotrombidium schlugerae, Leptotrombidium album, and Ascoschoengastia latyshevi were first recorded on bats in the temperate zone of eastern Russia. L. schlugerae was more abundant than A. latyshevi in the same study sites in Eastern Siberia, and the main hosts of both chigger species were Plecotus ognevi and Eptesicus nilssonii. Ixodid ticks Dermacentor marginatus, Ixodes simplex, and Ixodes sp. were sampled from bats in Kazakhstan, the Far East, and Eastern Siberia, respectively. Phylogenetic analysis based on Cox1, 16S rDNA, and ITS2 sequences of I. simplex showed that the specimens from the Far East grouped into a clade distributed in the Eastern Palaearctic and India. In turn, the specimen of Ixodes sp. from Eastern Siberia was most closely related to Ixodes soricis and Ixodes angustus with p-distance of 9.8-10.7% (Cox1), suggesting that this tick probably belongs to a new species. Argas vespertilionis larvae were collected from three widespread bat species in Kazakhstan. Two bug species, Cimex pipistrelli and Cimex aff. lectularius, were recorded in the Far East and Eastern Siberia, respectively. Specimens from Transbaikalia were morphologically identified as Cimex lectularius. However, they differed from the latter by 12.5-12.9% of Cox1 sequences, indicating that C. aff. lectularius may be a new species.


Assuntos
Argasidae , Percevejos-de-Cama , Quirópteros , Ixodes , Ixodidae , Trombiculidae , Animais , Filogenia , Larva
7.
Trans R Soc Trop Med Hyg ; 118(3): 206-222, 2024 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-37972992

RESUMO

Scrub typhus is one of the most neglected tropical diseases, a leading cause of acute undifferentiated febrile illness in areas of the 'tsutsugamushi triangle', diagnosed frequently in South Asian countries. The bacteria Orientia tsutsugamushi is the causative agent of the disease, which enters the human body through the bite of trombiculid mites (also known as chiggers) of the genus Leptotrombidium deliense. Diagnosis of the disease is challenging, as its early symptoms mimic other febrile illnesses like dengue, influenza and corona viruses. Lack of rapid, reliable and cost-effective diagnostic methods further complicates the identification process. Northeast India, a mountainous region with a predominantly rural tribal population, has witnessed a resurgence of scrub typhus cases in recent years. Various ecological factors, including rodent populations, habitat characteristics and climatic conditions, influence its prevalence. Entomological investigations have confirmed the abundance of vector mites, highlighting the importance of understanding their distribution and the probability of transmission of scrub typhus in the region. Proper diagnosis, awareness campaigns and behavioural interventions are essential for controlling scrub typhus outbreaks and reducing its impact on public health in Northeast India. Further research and community-based studies are necessary to accurately assess the disease burden and implement effective prevention strategies.


Assuntos
Orientia tsutsugamushi , Tifo por Ácaros , Trombiculidae , Animais , Humanos , Tifo por Ácaros/diagnóstico , Tifo por Ácaros/epidemiologia , Tifo por Ácaros/microbiologia , Trombiculidae/microbiologia , Reservatórios de Doenças , Índia/epidemiologia
8.
Jpn J Infect Dis ; 77(1): 55-58, 2024 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-37648489

RESUMO

To demonstrate the transmission cycle of Shimokoshi-type Orientia tsutsugamushi in Shimane Prefecture, field rodents were captured from areas where four human infections caused by the pathogen have been reported. The rodents were investigated for the transmission cycle of the pathogen based on the pathogen's genome, antibodies against the pathogen, and the vector of the pathogen (Leptotrombidium palpale). In addition, the vector was captured from the soil in the study area. A total of 44 rodents were captured. No O. tsutsugamushi DNA was detected in the blood or spleen samples by real-time polymerase chain reaction. However, a specific antibody against the pathogen was detected in 2 out of 44 (4.5%) rodents using the indirect immunoperoxidase method, indicating the presence of the pathogen in the study area. Although 29 L. palpale were identified, DNA detection was not performed because of the insufficient number of vectors, based on the DNA detection rate in previous studies. However, the identification of the vector, as well as the specific antibody in rodents, suggests the presence of the transmission cycle of Shimokoshi-type O. tsutsugamushi in Shimane Prefecture.


Assuntos
Orientia tsutsugamushi , Tifo por Ácaros , Trombiculidae , Animais , Humanos , Orientia tsutsugamushi/genética , Japão/epidemiologia , Tifo por Ácaros/epidemiologia , Tifo por Ácaros/diagnóstico , Trombiculidae/genética , Roedores/genética , DNA
9.
Exp Appl Acarol ; 91(3): 439-461, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37870736

RESUMO

Chiggers are common ectoparasites and the exclusive vector of scrub typhus. Based on previous investigations from a unique geographical area in Yunnan Province of southwest China, the Three Parallel Rivers Area, we retrospectively studied the species diversity and related ecology of chiggers on rodents and other small mammals. A very high species diversity of 120 chigger species was identified. Five dominant chigger species accounted for 59.4% (5238/8965) of total chiggers, and among them Leptotrombidium scutellare is the second major vector of scrub typhus in China. Species diversity of the chigger community fluctuates greatly in different altitudinal and latitudinal gradients. There are significant differences in species composition, species diversity and dominant species of chiggers among hosts with apparent community heterogeneity. Based on the species abundance distribution, the expected total number of chigger species was estimated to be 170, 50 more than the number of actually collected species; this further indicates a very high chigger species diversity in this area. The bipartite ecological network analysis revealed the intricate relationships between chigger and host species-positive and negative correlations existed among some species of dominant and vector chiggers.


Assuntos
Infestações por Ácaros , Doenças dos Roedores , Tifo por Ácaros , Trombiculidae , Animais , Estudos Retrospectivos , China , Mamíferos/parasitologia , Infestações por Ácaros/parasitologia , Roedores/parasitologia
10.
Syst Parasitol ; 100(6): 687-695, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37861862

RESUMO

Few studies have been carried out on the Ecuadorian chigger fauna. In this study, we are describing a new species of Eutrombicula from the Galápagos Islands. Also, we provide an updated checklist of Ecuadorian and Galápagos Islands chiggers, including a new host association and locality record for Eutrombicula nerudai Stekolnikov and González-Acuña.


Assuntos
Infestações por Ácaros , Trombiculidae , Animais , Equador , Lista de Checagem , Especificidade da Espécie
11.
Nat Ecol Evol ; 7(11): 1856-1868, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37813943

RESUMO

Predicting future evolutionary change is a critical challenge in the Anthropocene as geographic range shifts and local extinction emerge as hallmarks of planetary change. Hence, spatial sorting-a driver of rapid evolution in which dispersal-associated traits accumulate along expanding range edges and within recolonized habitats-might be of growing importance in ecology and conservation. We report on the results of a natural experiment that monitored recolonization of host plants by the seed-feeding, red-shouldered soapberry bug, Jadera haematoloma, after local extinctions from catastrophic flooding in an extreme hurricane. We tested the contribution of spatial sorting to generate rapid and persistent evolution in dispersal traits, as well as in feeding traits unrelated to dispersal. Long-winged dispersal forms accumulated in recolonized habitats and due to genetic correlation, mouthparts also became longer and this shift persisted across generations. Those longer mouthparts were probably adaptive on one host plant species but maladaptive on two others based on matching the optimum depth of seeds within their host fruits. Moreover, spatial sorting eroded recently evolved adaptive divergence in mouthpart length among all host-associated biotypes, an outcome pointing to profound practical consequences of the extreme weather event for local adaptation, population resilience and evolutionary futures.


Assuntos
Tempestades Ciclônicas , Sapindus , Trombiculidae , Animais , Ecossistema , Ecologia , Plantas
12.
J Parasitol ; 109(5): 514-524, 2023 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-37821100

RESUMO

The chigger species Acomatacarus coahuilensis n. sp. (Acariformes: Trombidiformes: Leeuwenhoekiidae) inhabiting the neck scales of the wary spiny lizard Sceloporus cautus Smith, 1938 (Squamata: Iguania: Phrynosomatidae), from Chihuahuan Desert Province, Coahuila, Mexico, is described herein. The new mite species is assigned to the genus AcomatacarusEwing, 1942, based on a palptarsus with 6 branched setae plus the tarsala (ω). This new species can be separated from the other species in this genus mainly based on the combination of the following characters: presence of mastisetae (MTa) on tarsus III and tibiala (φ) on tibia III, subterminala (ζ1), parasubterminala (z), and pretarsala (ζ2) on tarsus I, 2 genualae (σ1-2) on genu I, onychotriches and claw-like empodium of legs I-III, and absence of mastisetae on tibia III. In addition to the new species, the gastrointestinal nematode Skrjabinoptera phrynosoma (Ortlepp, 1922) Schulz, 1927 (Physalopteridae), was also found, which represents a new host record in the wary spiny lizard. This study reports the third species of the genus Acomatacarus recorded from Mexico and the first record of chigger mites and helminth parasites associated with Sc. cautus.


Assuntos
Helmintos , Lagartos , Nematoides , Trombiculidae , Animais , México/epidemiologia , Lagartos/parasitologia
13.
Vet Med Sci ; 9(6): 2920-2926, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37725255

RESUMO

As a group of ectoparasites, chiggers (larvae of chigger mites) are the exclusive vector of scrub typhus (tsutsugamushi disease). Rodents are the most important hosts of chiggers. The Anderson's niviventer rat, Niviventer andersoni, is an endemic species of rodent in China. However, few studies have involved this endemic rodent species and its ectoparasites including chiggers. According to the field investigation in five provincial regions of southwest China between 2001 and 2019, this paper retrospectively analysed the infestation and distribution of chiggers on the body surface of N. andersoni in southwest China for the first time. From 77 Anderson's niviventer rats captured, a total of 527 chiggers were collected and they were identified as 39 species and nine genera in two subfamilies of family Trombiculidae. Of 39 chigger species identified, Leptotrombidium deliense and L. scutellare are the most important vectors of scrub typhus in China. The overall infestation indexes were PM = 29.87%, MA = 6.84 and MI = 22.91, and the indexes of chigger mite community were Mf = 39, H' = 2.60, E = 0.71 and D = 0.12. The dominant chigger species are L. wenense, L. xiaguanense and L. fujianense with a total Cr = 51.04%, among which L. wenense is one of the six main vectors of scrub typhus in China. The dominant chigger species are of aggregated distribution among different individuals of the rats.


Assuntos
Doenças dos Roedores , Tifo por Ácaros , Trombiculidae , Ratos , Animais , Tifo por Ácaros/epidemiologia , Tifo por Ácaros/veterinária , Estudos Retrospectivos , Roedores/parasitologia , China/epidemiologia , Doenças dos Roedores/epidemiologia , Doenças dos Roedores/parasitologia
14.
PLoS Negl Trop Dis ; 17(9): e0011412, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37747922

RESUMO

BACKGROUND: Scrub typhus is a potentially fatal acute febrile illness caused by bacteria in the genus Orientia. Though cases have been documented, a comprehensive body of evidence has not previously been compiled to give an overview of scrub typhus in Indonesia. This study aimed to address this key knowledge gap by mapping and ranking geographic areas based on existing data on the presence or absence of the pathogen in humans, vectors, and host animals. METHODOLOGY/PRINCIPAL FINDINGS: We performed searches on local and international electronic databases, websites, libraries, and collections including Embase, Medline, and Scopus to gather relevant evidence (including grey literature). After extracting data on the presence and absence of the pathogen and its vectors, we ranked the evidence based on the certainty for the presence of human infection risk. The country was divided into subnational units, and each were assigned a score based on the evidence available for that unit. We presented this in an evidence map. Orientia tsutsugamushi presence has been identified on all the main islands (Sumatra, Java, Borneo, Celebes, Papua). About two thirds of the data points were collected before 1946. South Sumatra and Biak had the strongest evidence for sustaining infectious vectors. There was only one laboratory confirmed case in a human identified but 2,780 probable cases were documented. The most common vector was Leptotrombidium deliense. CONCLUSIONS/SIGNIFICANCE: Our review highlights the concerning lack of data on scrub typhus in Indonesia, the fourth most populous country in the world. The presence of seropositive samples, infected vectors and rodents confirm O. tsutsugamushi is widespread in Indonesia and likely to be causing significant morbidity and mortality. There is an urgent need to increase surveillance to better understand the burden of the disease across the archipelago and to inform national empirical fever treatment guidelines.


Assuntos
Orientia tsutsugamushi , Tifo por Ácaros , Trombiculidae , Animais , Humanos , Tifo por Ácaros/epidemiologia , Tifo por Ácaros/microbiologia , Indonésia/epidemiologia , Trombiculidae/microbiologia , Roedores/microbiologia , Febre
15.
Vector Borne Zoonotic Dis ; 23(12): 619-633, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37625029

RESUMO

Background: Orientia tsutsugamushi is a zoonotic intracellular pathogen that requires parasitism in eukaryotic cells to reproduce. In recent years, tsutsugamushi disease reported in many places nationwide has crossed the Yangtze River, continuously, spreading to the North China. Now this phenomenon has aroused people's attention. Materials and Methods: In this study, meta-analysis was used to analyze the infection of rodents (vectors) in China, to clarify the transmission rule of O. tsutsugamushi. Results: This study included literature from six databases (PubMed, Web of Science, Science Direct, Wanfang, CNKI, and VIP). A total of 55 articles were included in the study from 610 retrieved articles. The total infection rate of O. tsutsugamushi in rodents was 5.5% (1206/20,620, 95% confidence interval [CI]: 0.0553-0.0617). The prevalence of O. tsutsugamushi in rodents before 2013 (7.73%, 95% CI: 4.11-12.37) was higher than after 2013 (2.11%, 95% CI: 0.64-4.41). O. tsutsugamushi spread among a variety of rodents, among which Rattus losea (13.3%, 95% CI: 4.33-26.26), Rattus tanezumi (5.69%, 95% CI: 1.37-12.72), and Apodemus agrarius (5.32%, 95% CI: 2.26-9.58) infection rate was higher. Kawasaki (8.32%, 95% CI: 1.42-20.17), Karp (7.36%, 95% CI: 2.62-14.22), Kato (2.54%, 95% CI: 0.08-8.28), and Gilliam (2.13%, 95% CI: 0.42-5.09) were the main prevalent genotypes in China. The prevalence of O. tsutsugamushi in rodents was seasonal, increasing gradually in summer (2.39%, 95% CI: 0.46-5.77), peaking in autumn (4.59%, 95% CI: 1.15-10.16), and then declining. The positive rate of immunofluorescence assay (25.07%, 95% CI: 8.44-46.88) was the highest among the detection methods, and it was statistically significant (p < 0.05). Based on the subgroup of geographical factors and climatic factors, the probability of O. tsutsugamushi infection in rodents was the highest when the temperature >19℃ (8.20%, 95% CI: 1.22-20.52), the altitude <100 millimeters (7.23%, 95% CI: 3.45-12.26), the precipitation >700 millimeters (12.22%, 95% CI: 6.45-19.50), and the humidity 60-70% (7.80%, 95% CI: 4.17-12.44). Conclusions: Studies have shown that rodents carrying O. tsutsugamushi are common. People should prevent and control rodents in life and monitor rodents carrying O. tsutsugamushi for a long time.


Assuntos
Orientia tsutsugamushi , Tifo por Ácaros , Trombiculidae , Animais , Humanos , Orientia tsutsugamushi/genética , Prevalência , Tifo por Ácaros/epidemiologia , Tifo por Ácaros/veterinária , Murinae , China/epidemiologia
16.
Parasites Hosts Dis ; 61(3): 272-281, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37648232

RESUMO

Chigger mites are the vector of scrub typhus. This study estimates the infestation status and ecological characteristics of chiggers on the chestnut white-bellied rat Niviventer fulvescens in Southwest China between 2001 and 2019. Chiggers were identified under the microscope, and infestation indices were calculated. The Preston's log-normal model was used to fit the curve of species abundance distribution. A total of 6,557 chiggers were collected in 136 of 342 N. fulvescens rats, showing high overall infestation indices (prevalence=39.8%, mean abundance=19.2, mean intensity=48.2) and high species diversity (S=100, H'=3.0). Leptotrombidium cangjiangense, Neotrombicula japonica, and Ascoschoengastia sifanga were the three dominant chigger species (constituent ratio=42.9%; 2,736/6,384) and exhibited an aggregated distribution among different rat individuals. We identified 100 chigger species, with 3 of them (Leptotrombidium scutellare, Leptotrombidium wenense, and Leptotrombidium deliense) as the main vectors of scrub typhus in China and nine species as potential vectors of this disease. Disease vector occurrence on N. fulvescens may increase the risk of spreading scrub typhus from rats to humans. Chigger infestation on N. fulvescens varied significantly in different environments. The species abundance distribution showed a log-normal distribution pattern. The estimated number of chigger species on N. fulvescens was 126 species.


Assuntos
Asteraceae , Infestações por Ácaros , Tifo por Ácaros , Trombiculidae , Humanos , Animais , Ratos , Murinae , China/epidemiologia , Vetores de Doenças
17.
Parasites Hosts Dis ; 61(3): 263-271, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37648231

RESUMO

The present study aimed to survey the prevalence of chigger mites and Orientia tsutsugamushi (O. tsutsugamushi) infection in the northern regions of Gangwon-do, Korea. From early February to early June 2015, a total of 17,050 chiggers were collected from striped field mice, Apodemus agrarius, in Cheorwon-gun, Hwacheon-gun, Yanggu-gun, and Goseong-gun, which are well-known endemic areas of scrub typhus in Korea. The chiggers were analyzed using molecular genomic methods, as previously described. Among the 7,964 identified chiggers, the predominant species was Leptotrombidium pallidum (76.9%), followed by L. zetum (16.4%), L. orientale (4.3%), L. palpale (0.3%), L. tectum (0.2%), and Neotrombicula tamiyai (1.8%). The chigger index (CI) was highest in Hwacheon (115.58), followed by Cheorwon (97.02), Yanggu (76.88), and Goseong (54.68). Out of the 79 O. tsutsugamushi-positive chigger pools, 67 (84.8%) were identified as the Boryong strain, 10 (12.7%) as the Youngworl strain, and only 2 were the Jecheon strain. Based on the high infestation of chiggers in striped field rodents and the high rate of O. tsutsugamushi infection in chigger mites, Hwacheon-gun and Cheorwon-gun are presumed to be high-risk areas for scrub typhus. Furthermore, L. pallidum, a major vector of scrub typhus, and the dominant O. tsutsugamushi serotype, the Boryong strain, were found in the northern regions of Gangwon-do, Korea.


Assuntos
Infestações por Ácaros , Orientia tsutsugamushi , Tifo por Ácaros , Trombiculidae , Animais , Orientia tsutsugamushi/genética , Tifo por Ácaros/epidemiologia , Prevalência , Infestações por Ácaros/epidemiologia , Murinae , República da Coreia/epidemiologia
18.
Parasitol Res ; 122(11): 2549-2555, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37642771

RESUMO

This case report describes the successful control of poultry red mite [PRM] (Dermanyssus gallinae) infestations in an experimental laying hen house via a combined use of cleaning and disinfection measure, the preventive application of a synthetic silica-based acaricide and frequent mite monitoring. The high number of PRM in the laying hen house was reduced by 99.8% by treatment with fluralaner (Exzolt®, MSD Animal Health Unterschleißheim, Germany; 0.5 mg/kg body weight via drinking water twice, 7 days apart). After the laying hens were removed, the hen house was dry-cleaned, wet-cleaned and disinfected. After drying, synthetic amorphous silica (Fossil Shield® instant white, Bein GmbH, Eiterfeld, Germany) was applied as a preventive measure before the hen house was restocked with pullets for two housing periods of 58 and 52 weeks. Over these periods (i.e. more than 2 years), no PRM was detected during mite monitoring at two-week intervals via tube traps and visual monitoring. This result therefore suggests that the combined use of appropriate chemical and physical prevention measures within an integrated pest management regime can be successfully used for the long-term control of PRM. This could reduce the use of acaricidal drugs, thereby helping maintain their efficacy.


Assuntos
Acaricidas , Infestações por Ácaros , Doenças das Aves Domésticas , Trombiculidae , Animais , Feminino , Aves Domésticas , Infestações por Ácaros/tratamento farmacológico , Infestações por Ácaros/prevenção & controle , Infestações por Ácaros/veterinária , Galinhas , Doenças das Aves Domésticas/prevenção & controle , Doenças das Aves Domésticas/tratamento farmacológico , Acaricidas/uso terapêutico , Controle de Pragas , Dióxido de Silício
19.
Exp Appl Acarol ; 91(1): 1-27, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37553534

RESUMO

Trombiculid mites were collected from the edible dormouse (Glis glis) within the Carpathian-Balkan distribution gradient of host species. Representatives of five genera (Leptotrombidium, Neotrombicula, Brunehaldia, Hirsutiella, Schoutedenichia) and 10 species of chiggers were discovered in the material, based on morphological and/or molecular data. Brunehaldia, new to the fauna of Greece, was recorded for the first time from the edible dormouse. Neotrombicula talmiensis was new to the fauna of Greece and Neotrombicula vulgaris was new to the fauna of North Macedonia. Successful amplification and sequencing of COI was carried out in relation to three genera and six species. The intraspecific variation of taxa hitherto distinguished based on morphological criteria was juxtaposed with molecular data, using the distance method and the phylogenetic approach. The molecular methods indicated wider than hitherto recognized, intraspecific morphological variation for Leptotrombidium europaeum and N. talmiensis. On the other hand, an inference limited to morphology proved to be insufficient for species delineation, which was confirmed by the relatively low identity (%) of examined COI sequences as well as the size of inter-/intraspecific K2P distance threshold. Our study provides support for integrative taxonomy that combines different sources of evidence and contributes to recognition of the scope of intraspecific variation. The high degree of hidden diversity revealed with the application of molecular tools, votes for a careful approach to the identification of chiggers. The confirmed cases of co-invasion, including the representatives of various genera (Leptotrombidium and Neotrombicula, Brunehaldia and Neotrombicula, Neotrombicula and Schoutedenichia, Hirsutiella and Schoutedenichia) additionally support the need to include all larvae found on a given host specimen in the identification process.


Assuntos
Infestações por Ácaros , Myoxidae , Doenças dos Roedores , Trombiculidae , Animais , Filogenia , Península Balcânica
20.
Emerg Infect Dis ; 29(8): 1676-1679, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37486323

RESUMO

Scrub typhus, a rickettsial disease caused by Orientia spp., is transmitted by infected larval trombiculid mites (chiggers). We report the molecular detection of Orientia species in free-living Eutrombicula chiggers collected in an area in North Carolina, USA, to which spotted fever group rickettsiae infections are endemic.


Assuntos
Orientia tsutsugamushi , Tifo por Ácaros , Trombiculidae , Animais , Estados Unidos/epidemiologia , Orientia tsutsugamushi/genética , Trombiculidae/microbiologia , Orientia , Tifo por Ácaros/diagnóstico , Tifo por Ácaros/epidemiologia , Tifo por Ácaros/microbiologia , Bactérias , Roedores
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